Duck-sbooting 71 



world, thou2fh more abundant in the northern 

 hemisphere. They differ from the mergansers 

 in havinor broad and flat bills with a series of 

 transverse grooves, instead of "teeth," on the cut- 

 ting surfaces : these grooves are of service in 

 straining out the water from the grasses and 

 other vegetable food which they procure when 

 swimming. The absence of a membranous lobe 

 on the hind toe separates them from the sea- 

 ducks and the mergansers, and their feet and 

 palmations are smaller than those of the former. 

 Their necks are rather short, and, as a rule, the 

 heads of the adult males without a crest. In many 

 of the species the males have a very elegant 

 plumage, as the wood-duck, differing from the 

 plainer females, and most have a bright metallic 

 patch of feathers on the wing. Frequently the 

 male has a summer moult, in which he assumes 

 a dull plumage, much resembling that of the 

 female. This lasts while the wing feathers are 

 growing, and is probably a great protection to 

 him during the days or weeks that he cannot fly ; 

 but early in the autumn he acquires again his 

 striking dress. 



The flight of all is swift and strong, and has 

 been thought in some species to reach a hundred 

 and fifty miles an hour. They spring from the 

 water at a bound, and are instantly under way. 

 Frequenting by preference fresh water, the river- 



